


With The Moon As My Witness

by thananteros



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Confessions, Drunken sex, M/M, Soft., i got sylvains s support and i stan one man
Language: English
Status: Completed
Published: 2019-09-26
Updated: 2019-09-26
Packaged: 2020-10-28 23:35:12
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,888
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20786906
Author URL: https://archiveofourown.org/users/thananteros/pseuds/thananteros
Summary: Byleth chooses the worst way to tell Sylvain.





	With The Moon As My Witness

**Author's Note:**

> i! am! soft! i love sylvain and this is completely self indulgent.

“Come on, professor.”

Bright red hair bounced as Sylvain trailed behind Byleth. The stoic man kept pretending to ignore the man as he worked away at making a supply list. After several moments of Sylvain’s whining he sighed and looked back at the man. That was a mistake since those brown eyes always squeezed at his heart. Byleth let out a small grumble and pinched the bridge of his nose.

“What is it, Sylvain? What do you want?” He was a mix of the constant exasperation and a light fluttery feeling from having the redhead’s attention. 

“Go out with me. Be my wingman tonight. The ladies can’t resist you and any boyfriends won’t wanna fight you.” He pleaded again. 

“Besides, if I fail we can just have a guy’s night. What do you say?”

Byleth couldn’t possibly actually be considering it. But unfortunately he had already sunk to falling to Sylvain’s every whim. He relented with a blank face.

“Fine. But I won’t be drinking. And I don’t want any of the women you hit on to touch me.” 

Warm eyes brightened and a hand ran through soft hair as Sylvain chuckled. 

“Easy. Done. Oh, and, don’t mention this to Ingrid, ok? I don’t want her thinking I’m a bad influence on you.” He joked lightheartedly, earning a very small snort from the professor.

———————

And so they went out that night. Sylvain had met Byleth outside the teacher’s room and led them to a small tavern in one of the nearby towns. Byleth had been in his fair share of places like this. But being there with the knowledge that Sylvain was going to leave with a girl made him a little less pleasant than usual.

“So how about it?” Sylvain’s voice broke through Byleth’s mental tirade of how much life sucked. The teacher’s blank eyes scanned around until they landed on the woman mostly in Sylvain’s lap. He bit back a scowl as she gushed over him. 

“How about what?” His tone was curt and emotionless, hiding the burning feeling growing behind his teeth and eyes as the woman pawed at the redhead.

Sylvain glanced over at the man, his cheeks a light pink and his eyes alight with mirth given by one too many drinks. 

“I was just asking this lovely lady if she’d like to get to know each other better.” He chuckled as he nosed at her neck. Bile rose in Byleth’s throat as he whipped his eyes away and downed the rest of his drink along with swiping and swallowing the redhead’s as well. 

Maybe that wasn’t the best idea. His head began to swim and his face warmed. He kept glancing back to Sylvain and saw the woman running her hand over the man’s chest. Byleth glared openly, a noise rising from his chest as the pair turned to face him with shocked expressions.

“What?” His tone was annoyed ashe clenched his teeth.

“If you’re not having fun you can leave.” The woman scoffed and ran a hand through Sylvain’s hair, ripping another growl from the teacher’s throat. 

“I think that’s a good idea.” He snapped as he stood quickly, knocking the table with his hip. The redhead startled as Byleth reached out and grabbed his arm roughly, tugging him away from the woman.

The professor’s mood worsened with Sylvain’s complaints as he pulled the man back to an inn they had rented for the night. His face showed more expression than ever as he slammed the door behind them and shoved Sylvain back on the bed.

“What the hell?” Any other question from the cavalier was abruptly cut off by Byleth climbing onto his lap and whimpering. 

Sylvain looked up at the man, the moonlight coming through the window and casting an ethereal glow on the professor’s hair and eyes. Eyes that had tears spilling out of them. 

“This might not be the right time. But you look beautiful right now, professor.” The silky words flowed from the playboy’s mouth as Byleth sniffled on top of him. The teacher wiped at his eyes before bending in half and pressing his lips to Sylvain’s cheek, much to the man’s surprise.

“Why did you let her touch you like that? Why would you make me have to see it? I wanna touch you. I wanna sit on your lap and have you kiss my neck.” The drunken words spilled out of the crying man’s lips in a stumbling attempt to feel better. Strong arms wrapped around his back, pulling him close in a crushing hug. 

“Goddess...if I though you wouldn’t cut my dick off I would have tried to bed you a long time ago.” Sylvain’s flirting caused a sob to wrack through Byleth’s body. Green eyes looked up at brown ones with determination. Byleth sat up and spread a hand on the redhead’s chest, eyes blown wide with emotion and alcohol.

“I’m gonna make it so you only ever look at me.”

Soft lips pressed against softer ones hungrily, pushing further until Sylvain opened his mouth with a soft gasp of surprise. Byleth took the opportunity to thrust his tongue inside the mouth and trail it along his teeth. He wrapped their muscles together and pulled Sylvain’s into his own mouth to suck and nibble it lightly. Soft moans came from the professor as his hands trailed carefully over Sylvain’s clothed body. 

Once he finally pulled back, both of their faces were flushed red and they were panting hot breaths into the cool air. Byleth gasped loudly when Sylvain rolled his hips up, causing a burning friction. The younger man doubled over and nuzzled against the older’s neck. He pressed soft kisses to heated skin as they rutted against each other. Large hands moved down to grope at Byleth’s ass through his pants, pulling the cheeks apart to thrust between them with a low moan. The green hired man keened and clenched around nothing before deciding enough was enough and stood on wobbly legs to try and undress. He ended up tearing his shirt off, the seams ripping from his desperation. Sylvain only chuckled and quickly slid his clothes off, more practiced in the art than his professor. 

“How long-how long have you felt like this?” The question floated in the air as Byleth straddled him again with a whine. 

“Since Felix and Annette’s wedding. You cried during your speech. It made me wanna suck your dick under the table.” 

The confession, however filthy it was, caused a thud in Sylvain’s chest. He didn’t know his teacher to lie. So this was a genuine confession.

“Well you’re welcome to anytime. But a guy like you should do that to someone you love. Don’t you think?” 

Byleth’s face contorted back into expressionless as Sylvain’s words registered. The man was stupid. Completely stupid. 

“How many times do I have to say that before you realize I love you? I stare at you all the time. I have dreams of washing your hair and kissing your nose. I hate seeing you flirt with girls because I know you hate them and I want to give all of myself to you. What else do you want me to say?”

Now they were both blushing even harder. Byleth’s face was set and determined, his courage boosted by the drinks he had. Sylvain whined and gripped pale, scarred thighs before lifting the smaller man up and throwing him back on the bed. Byleth gasped and spread his legs, wrapping them around Sylvain’s waist and pulling the man closer. 

“Please, Sylvain, please. Fuck me.” The teacher started a chant, his face red but blank. The only giveaway to his impatience was his grinding body and pitchy pleas. The redhead couldn’t say no to that, not that he could say no to his professor anyway. He dove down and captured the moving lips as he pressed against the man. 

“Do you have oil?” Byleth blinked, stunned at the question. Why would they meed oil? Oh! Right. He wrapped his arms around Sylvain’s neck and pulled him back down. 

“Trust me, I’m wet enough.” And true to his words, his backside was slippery with his slick. The feeling sent a shiver down the redhead’s spine.

“Hot, kinda weird though.” He snickered at Byleth’s embarrassed huff and pushed forwards slowly. His head popped into the hole without him pressing hard at all. The cavalier raised an eyebrow in question.

“I think about you every day.” Was the only response he got before Byleth thrust back and impaled himself on Sylvain’s member with a cry. He threw his head back and arched his back as he pleaded for the man to move. Sylvain grinned and complied, setting a rhythm of thrusts that shook the bed under them. 

“Who knew you were this willing with your body?” Sylvain teased as he nipped at the teacher’s ear, earning a whimper and a squeeze. 

Before he could muster an answer Byleth screamed and scratched at Sylvain’s back. Pleasure coursed through him as the redhead adjusted to hit right there every time. Heat flooded Byleth’s body, his mind swimming in lust and adoration of the man inside of him. 

The two set a steady rhythm, the air around them heating up with their noises of pleasure. The pattern was broken when Byleth screwed his eyes shut and came with a cry of Sylvain’s name. 

Said redhead finished soon after, plunging into his teacher and filling him with seed. Stars were in both of their eyes for the short moment they remained awake. 

—————

That next morning when Sylvain had awoken, he had been alone. He didn’t see the professor again other than brief glances for several days. Finally he was fed up with it and cornered the green haired man in the greenhouse. 

“What happened that night?” His voice was steady to cover up how nervous he was. He wanted to whine and pout, after all, the only thing he had on his mind was Byleth. 

“What night? There’s at least one every day.” Ok. Stupid. Very stupid. 

“You know what night. You said you were gonna make me look only at you. Or something like that.” Why was it always night time during scenes like this? Byleth didn’t have the right to be as beautiful as he was while Sylvain was mad at him.

Said beautiful man bit his lip and looked away. He supposed he owed him an explanation. 

“I meant whatever I said. But I know you feel like you have a duty. So I won’t get in the way of you being happy.” He was barely done with the last word before his lips were captured and his breath was stolen. He whimpered and kissed back, running his fingers through Sylvain’s soft hair before they parted. 

“Say it.” The cavalier pleaded.

“I love you. I want you.” Byleth responded in a soft voice.

“You have me. I’ve always known you to be too good for me. I didn’t chase you because of that. But you have me. By the heart, the neck, the dick. If..if you want. Will you be mine?” 

Byleth nodded, tears flowing from his eyes as he pulled Sylvain into a hug. 

“Yes. I will.” A promise spoken in the dim light of the night. Forever to bind them.


End file.
